In 11 patients treated thus far, nine achieved complete healing that has been durable out to at least 1 year, said Amy Lightner, MD, of the Mayo Clinic, Rochester, Minn., and colleagues, in a poster presentation at the annual Digestive Disease Week.

She added that the two patients who had not achieved complete healing should not be considered failures at this point, just patients with slower healing of their fistulas.

In the phase I trial, the patients' own adipose tissue were used to harvest mesenchymal stem cells. "We grow these cells to get millions of them, and then we soak the plug with these cells and then put the plug in the fistula," Lightner explained. The cells then incorporate themselves into the patients' tissue.

All 11 patients with Crohn's disease (four women; seven men) had lived with the fistulas for an average of more than 4 years and had, on average, seven prior surgeries. Treatments for perianal fistulas include various surgical procedures, but generally they all leave the patient with a reduced quality of life. "There are lots of things we can do, but none of them are very effective," she said.

The plug is about 5-6 in in length, and is sutured in place, with the excess length trimmed.

Patients underwent exam under anesthesia for control of perianal sepsis and seton placement with simultaneous abdominal wall adipose tissue biopsy, the authors explained.

Six weeks after seton placement, the MSC-coated fistula plug was surgically placed, and patients were followed with serial exams, serum lab draws, and MRI evaluation for fistula healing.

"Complete healing was defined clinically as complete cessation of drainage, and the characteristics of these healed fistulas was defined by serial MRI," they wrote.

"Usually, by 2 to 4 weeks the patients say they have improvement in their condition," Lightner noted.

Placement of the stem cell-coated fistula plug was not associated with any perioperative adverse events, the group noted, and there have been no cases of plug migration. To date, there have been no fistula recurrences. she said.

"This is a terrible condition," Lightner said. "It is very morbid and we don't have good therapies for it. Getting resolution of this with the plug is just great for the patients."

However, Lightner cautioned that the small study population was a limitation. In addition, it is an expensive procedure and not ready for prime-time.

"We are still in a clinical trial mode," she said. "But if there was funding for this, this is absolutely what I would do for my patients. It is every effective."

"It is very fair to characterize this as promising," said Neil Hyman, MD, of University of Chicago Medicine. But he noted that surgeons who treat perianal fistulas are skeptical of new procedures because others have failed in the past.

"In previous studies using these types of techniques, the outcomes have been plagued by recurrence," he said. "We really don't know all the mechanisms of how this works, and therefore we don't know the optimal way to apply these stem cells."

Hyman acknowledged that patients with perianal Crohn's disease currently have limited treatment options. "The outcomes with medical therapy are at best suboptimal; the most common way we treat patients with Crohn's disease and fistulas is that we palliate them, rather than cure them," he stated. "What is exciting about this procedure is the opportunity to offer a cure, or a resolution, of the fistula, which historically has only applied to a small minority of patients with Crohn's disease."

Lightner disclosed no relevant relationships with industry.

Hyman disclosed no relevant relationships with industry.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner